Sensors, Actuators & Embedded Boards
JKSSB Sub-Inspector (Telecommunication) · IoT, Embedded Systems & Mechatronics · 20 practice questions with answers and explanations: 12 Easy, 8 Medium, 0 Hard.
Sample questions
Sample Easy question 1
What logic level do the GPIO pins of a Raspberry Pi use?
- 5 V
- 1.8 V
- 3.3 V
- 12 V
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Answer: C. Raspberry Pi GPIO is 3.3 V and is not 5 V tolerant.
Sample Easy question 2
What is the purpose of a pull-up resistor on a switch input?
- To keep the input at a defined HIGH level when the switch is open
- To increase the supply voltage
- To measure the switch current
- To store the switch state
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Answer: A. Without it the input would 'float' and read random values.
Sample Easy question 3
Which serial bus uses the four lines MOSI, MISO, SCK and SS?
- UART
- SPI
- CAN
- I²C
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Answer: B. SPI is a fast synchronous bus with a separate select line per device.
Sample Medium question 4
How many analog input pins does the Arduino Uno have?
- 6
- 2
- 14
- 8
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Answer: A. The Uno has 6 analog inputs (A0 to A5) and 14 digital I/O pins.
Sample Medium question 5
What range of values does analogRead() return on an Arduino Uno?
- 0 to 255
- 0 to 4095
- 0 to 100
- 0 to 1023
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Answer: D. The Uno's ADC is 10-bit, so it gives 2^10 = 1024 levels.
Sample Medium question 6
What does PWM (pulse width modulation) do?
- Varies the duty cycle of a digital signal to control average power
- Measures temperature
- Converts light into voltage
- Stores data in memory
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Answer: A. Changing the on-time fraction controls motor speed or LED brightness.